Weatherly, who plays Special Agent Tony DiNozzo, has been with "NCIS" since it debuted in 2003.

In postings on his Twitter account Tuesday, Weatherly thanked the show's fans worldwide and said "NCIS" was a "fantastic ride." He called DiNozzo a wonderful character, one who was fun to play.

In a statement, CBS said Weatherly will leave "NCIS" at the end of this season. The network said it looked forward to working with Weatherly as part of its ongoing development deal with him.

Mark Harmon stars in the top-rated drama about Naval Criminal Investigative Service agents in Washington. The show is part of a popular franchise for CBS, with other "NCIS" series set in Los Angeles and New Orleans.